What is the Easiest way to Animate the rigid body properties of a large group of objects
[Select the rigid body object and copy their properties (except for animated).]


Select all rigid body object to be modified.
Alt click on the Animated property. This will change the property for all the selected object to the same value. Now all object have animated enabled.
Use this script to key the property on all of them.  




import bpy
sel = bpy.context.selected_objects
for ob in sel:
    ob.rigid_body.keyframe_insert(data_path="enabled") 
    ob.rigid_body.keyframe_insert(data_path="kinematic")


Now all objects are keyed.

To remove all Animated keys on a frame, execute the script but replace keyframe_insert with keyframe_delete.